This invention relates to computer networks. In particular, the invention relates to interfacing between a network interface and a bus.
Technologies for computer networks have advanced at a fast rate to accommodate the needs for efficient and reliable communication. Designs for computer networks are now becoming complex both in hardware and software. To reduce complexity, most computer networks are organized as a series of layers or protocols, each one built upon the one below it. The function of each layer is to provide certain services to the higher layers, shielding those layers from the specific and detailed implementation of these services.
A network architecture typically follows some reference model to maintain universality and standardization. Examples of important reference models include the broadband Integrated Services Digital Network (B-ISDN) Asynchronous Transfer Mode (ATM), the Open System Interconnection (OSI), and the Transmission Control Protocol/Internet Protocol (TCP/IP) reference models. In general, a network architecture has the following layers: application, transport, network, data link, and physical. In these layers, the actual data transmission takes place in the physical layer.
For ATM communications systems, the Universal Test and Operations PHY Interface for ATM (UTOPIA) parallel data interface is an industry standard for communications between an upper ATM layer module and a Physical Layer module. Thus, vendors providing particular physical layer transceivers often include the physical layer UTOPIA interface as part of their chipset functionality.
Modern microprocessor systems typically have a bus interface to allow bus masters (e.g., the host processor in the system) to communicate with peripheral devices. A particular system bus may become popular due to widespread usage and standardization. Examples of popular buses include the Peripheral Component Interface (PCI), Universal Serial Bus (USB), and 1394 Bus.
A method and apparatus are described for interfacing between a network interface and a bus.
For the network interface-to-bus side, the method comprises (a) forming a network address of a message transferred via the network interface to the bus, and (b) mapping the network address to a bus address of the bus, the bus address being within an address space occupied by a bus device coupled to the bus.
For the bus-to-network interface side, the method comprises (a) forming a bus index from a bus address of the bus where the bus address is within an address space occupied by a bus device coupled to the bus; and (b) mapping the bus index to a network address of a message transferred via the network interface to the bus.
Other features and advantages of the invention will be apparent from the detailed description and drawings provided herein.